1. Field of the Invention
The present invention is directed toward a network interface card which allows access to its resources even when the host computer is turned off. More particularly, the present invention is directed toward a network interface card which provides an alternate access path to its resources when the host computer is turned off.
2. Description of Related Art
Current NICs do not allow access to resources such as its transmit packet buffer, receive packet buffer, and registers when the host computer is powered down and main power is not available. This means that the PC must be powered up for the NIC resources to be accessed and for diagnostic and other PC management functions to be performed.
Current NICs do not offer alternate paths for accessing the NIC registers other than the main interface bus, typically the PCI bus. This means that the PC must be powered up for interface power to be provided to the main interface bus, such as PCI power to the PCI bus, in order for any access to the NIC registers to take place.
What is needed is a method and apparatus for allowing NIC resources to be accessed through auxiliary power and an ASIC clock while the PC is powered down and while PCI power and the PCI clock are not available. What is also needed is an alternate path for accessing the NIC registers, downloading keep-alive and alert-on-LAN packets to the transmit packet buffer (TPB), as well as uploading received packets from the receive packet buffer (RPB). What is also needed is a method and apparatus for monitoring PCI activity and seamlessly servicing the PCI configuration cycle (when PCI power and the PCI clock are restored) in conjunction with responding to the access through the alternate path (while PCI power and the PCI clock are not available).
The present invention is directed towards a network interface card. The network interface card comprises an alternate access path for allowing access to resources of the network interface card when the network interface card is in a low power consumption mode, and a clock control for supplying an ASIC clock signal to the network interface card when the network interface card is in a low power consumption mode, the ASIC clock signal providing a clock signal for the alternate access path. The network interface card also comprises a PCI activity monitor capable of detecting a PCI configuration cycle from a PCI host addressed to the network interface card when the network interface card is in the low power consumption mode, the PCI activity monitor capable of sending a stop request to the alternate access path, the PCI activity monitor capable of sending a retry signal to the PCI host, the PCI activity monitor capable of instructing the clock control to switch from the ASIC clock signal to a PCI clock signal in response to detecting the PCI configuration cycle, the PCI clock signal providing the clock signal to the network interface card to service the PCI configuration cycle.